FXUS63 KLSX 251721
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1121 AM CST WED NOV 25 2009

.DISCUSSION...
/403 AM CST WED NOV 25 2009/

TRADING ONE LOW FOR ANOTHER TODAY AS YESTERDAY'S SHORTWAVE MOVES 
EAST-NORTHEAST INTO THE GREAT LAKES REGION AND THE SECOND WAVE IN 
LINE DROPS THROUGH THE DAKOTAS INTO THE MID-MISSISSIPPI VALLEY.  
THIS SECOND SHORTWAVE WILL BRING A REINFORCING SHOT OF COLD 
AIR...AND POTENTIALLY ANOTHER SHOT AT SOME PRECIPITATION.  THE FIRST 
SHOT WILL BE LATER TODAY AS THE ASSOCIATED SURFACE FRONT MOVES 
THROUGH THE REGION.  THERE MAY BE JUST ENOUGH MOISTURE LEFT IN THE 
LOW LEVELS TO PRODUCE SOME LIGHT RAIN OR SPRINKLES BEHIND THE FRONT 
TODAY...BUT THE CHANCES ARE PRETTY LOW THAT THERE WILL BE ENOUGH 
PRECIPITATION TO MEASURE.  THINK THE BETTER CHANCE IS STILL TONIGHT 
AS THE WAVE MOVES INTO SOUTHERN IOWA/NORTHERN MISSOURI/WEST CENTRAL 
ILLINOIS.  GFS IS STILL SLIGHTLY FURTHER SOUTH WITH THE POSITION OF 
THE UPPER LOW AND THEREFORE IT WRAPS WARM AND MOIST AIR ALOFT 
FURTHER BACK INTO NORTHEAST MISSOURI AND WEST CENTRAL AND EVEN 
SOUTHWEST ILLINOIS.  THE NAM/ECMWF/GEM ARE FURTHER NORTH WITH THE 
LOW AND THIS WARM MOIST TONGUE IS MOSTLY OUT OF OUR AREA.  HAVE 
CONTINUED TO FOLLOW THE NAM/ECMWF/GEM CONSENSUS WHICH ONLY CALLS FOR 
MID-LOW CHANCE POPS OVER NORTHERN PORTIONS OF THE CWFA RATHER THAN 
LIKELY AS THE GFS SUGGESTS.  REGARDLESS OF THE MODEL...TEMPERATURES 
SHOULD BECOME COLD ENOUGH FOR A MIXTURE OF RAIN/SNOW...POSSIBLY 
CHANGING TO ALL SNOW LATE TONIGHT.  ANY SNOW THAT FALLS LOOKS TO BE 
VERY LIGHT SO I DON'T EXPECT ANY ACCUMULATION.

CLOUDS AND COOL TEMPERATURES WITH AN OCCASIONAL FLURRY OR SPRINKLE 
WILL CONTINUE ON THANKSGIVING MORNING...BUT RH PROGS ARE HINTING 
THAT THE CLOUDS COULD BREAK UP FROM WEST TO EAST DURING THE 
AFTERNOON AS THE SYSTEM MOVES EAST.  LOOKS LIKE CENTRAL MISSOURI 
COULD SEE QUITE A BIT OF SUNSHINE IN THE AFTERNOON...BUT CLOUDS 
MIGHT LINGER TOO LONG OVER SOUTHWEST ILLINOIS AND IT'S SOMEWHAT 
DOUBTFUL WHETHER THE SUN WILL BREAK OUT BEFORE IT SETS.

REMAINDER OF THE FORECAST IS BASICALLY UNCHANGED...FREEZING 
TEMPERATURES ARE EXPECTED OVER MUCH OF THE AREA ON FRIDAY 
MORNING...BUT IT LOOKS LIKE WE'LL SEE RETURN FLOW ON FRIDAY 
AFTERNOON THROUGH SATURDAY BRINGING MODERATING TEMPERATURES TO THE 
REGION.

CARNEY
&&

.AVIATION...
/1121 AM CST TUE NOV 24 2009/

FOR THE 18Z TAFS...MVFR/IFR CIGS HAVE EXITED TO THE EAST OF TAF 
SITES THIS MORNING. SO WILL SEE VFR CIGS TIL AFTER 04Z FOR 
KCOU...KSUS AND KSTL...THEN LOWER BACK DOWN TO MVFR. HOWEVER...WITH 
NEXT SHORTWAVE APPROACHING...KUIN WILL SEE CIGS LOWER TO MVFR 
SOONER...BY 21Z AND PERSIST THROUGH REST OF TAF VALID PERIOD. 
ALSO...PCPN CHANCES TO CONSIDER...MAINLY FOR KUIN. KEPT SNOW/RAIN 
SHOWERS IN FROM 04Z TO 08Z TONIGHT...THEN JUST SOME SPRINKLES/ 
FLURRIES TIL 14Z. AS FOR WINDS...GUSTY WEST WINDS TO DIMINISH THIS 
EVENING FOR KCOU...KSUS AND KSTL...THEN PICKUP ONCE AGAIN TOMORROW. 
WINDS TO REMAIN GUSTY AT KUIN.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$
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